The present invention relates to a fitting for a vehicle seat, in particular a latching fitting for a motor vehicle seat.
WO 00/44582 discloses a known latch fitting. In the event of a severe load in the direction of rotation, for example in the case of a crash, in which, via the backrest, a torque acts on the fitting part connected thereto, there is the risk, if the guide and the latches which are present are not produced with precise tolerances, of the latches tilting in the guide and, as a consequence, of the toothed overlap between the latch and fitting part being reduced.
One aspect of the present invention is the provision of an improved latch fitting that is suitable for relatively high load requirements and can be provided in a cost-effective manner. In accordance with this aspect, a fitting for a vehicle seat, in particular a latching fitting for a motor vehicle seat, has a lower fitting part, an upper fitting part which can be rotated relative to the lower fitting part, and at least one latch and an eccentric that are cooperative for selectively restricting the rotation of the upper fitting part. The latch is arranged for moving radially in a guide of the lower fitting part. The eccentric is for rotating relative to the fitting parts. When the eccentric rotates, it acts on a radially inward side of the latch, so that the latch moves radially outward and a radially outward side of the latch interacts with the upper fitting part via a meshing of teeth. The meshing restricts the rotation of the upper fitting part. The eccentric acts on the latch via two spaced-apart points.
By the eccentric acting on the latch via two spaced-apart points, the latch, when it receives a load which acts in the circumferential direction and which it experiences when the upper fitting part is loaded, can be better supported on the eccentric, i.e. a blocking force having a relatively large lever arm can oppose possible tilting in the guide. This retains the toothed overlap between the latch and the upper fitting part and therefore ensures the locked state. A considerable increase in load is therefore possible. Since toothed segments are not able to tilt as much, there is simultaneously an improved performance in terms of play.
Preferably, two eccentric cams are arranged on the eccentric and two blocking cams are arranged on the latch, in each case the cams are spaced part by a distance approximately equal to the latch width, as measured transversely to the guide. Apart from the improved support, this has the advantage of reducing the actuating path, since the latch can be activated more easily. The arrangement of the blocking cams and eccentric always ensures that an equilibrium of forces can arise, even under manufacturing tolerances. The bearing between the blocking cams and eccentric takes place within the self-locking range, in order to prevent a transmission of torque to the eccentric. In the case of two latches, the load is mainly conducted diagonally through the eccentric via respective blocking cams, with the result that despite the theoretically four-way support the static precision is maintained.
The play, which has already been reduced by the double support, is preferably further reduced by the eccentric cams having clamping surfaces with different average distances from the center of the eccentric. A tilting movement, which is caused thereby, of the latches, which are movable in the guides owing to tolerances, compensates for the free play. A suitable configuration ensures that the fitting has a low amount of play and great strength.